1. Field of the Invention
This invention relates in general to the field of implantable breast prostheses, and more particularly to those breast prostheses which are stacked.
2. Description of the related art
Implantable breast prostheses are used primarily in two ways:
1. Augmentation implants: augmentation mammoplasty is used to modify the size and/or shape of an intact breast.
2. Reconstructive implants: reconstructive mammoplasty is used to restructure the area in which a breast has been previously removed or modified.
Various types of implants have been used. In early attempts at breast modification simple injections of material directly into the breast parenchyma was sometimes attempted. This generally was not successful because the injected material would disperse or could not be contoured to give the desired shapes.
Later attempts used discrete implants, usually a single chamber implant filled with a silicone product (see: 3,665,520; 3,681,787; 4,455,691; 4,472,226; 4,573,999; 4,772,284). A problem with this type of implant is that they generally come in one size, can not be individually contoured to the individual patent, they may not give a normal contour to the modified breast, and they require relatively large incisions to insert them. Some implants do have a contoured or irregular shape, but these usually have a single chamber and when suspended in the human breast these tend to deform with most of the filling material pulling the prosthesis down into a pendulous or pear-shape, and these still usually require a large incision. If rigid shapes are used, then the implant gives the breast an abnormal texture or feeling and are difficult to insert and require large incisions.
Some prostheses have used multiple chambers (see 4,507,810 with multiple intercommunicating chambers). Many of these do not impart a normal contour to the reconstructed or augmented breast. These cannot be adjusted or "customized" for the individual recipient, and they may require large incisions.
Recently, some surgeons have used "stacked" implants. These generally consist of two implants stacked upon each other as needed in the mammoplasty process. However, there has been a problem with this type of implant procedure since the stacked implants tend to drift apart. Also, they may turn in relation to each other and in relation to the breast and they cannot be kept in an eccentric position relative to each other.